Locking means for cam operated chasers



Dec. 18, 1956 D. STERN 2,774,083

LOCKING MEANS FOR CAM OPERATED CHASERS Filed Sept. 9, 1954 INVENTOR. Dur Si'erh,

United States Patent C LOCKING RIEANS FOR CAM OPERATED CHASERS Claims.

The present invention relates to important improvements in the manufacture of screw cutting devices, mandrels and the like. The object of the present invention is to reduce the cost of such devices by simplifying and eliminating complicated parts, difiicult to adjust and cost- 1y to manufacture.

A typical example is that of the ordinary taps and dies, in that the member which provides for the advancing and correct positioning of the edges that cut the thread, must .be mounted with a high degree of accuracy, and with minimum tolerance, the manufacturing of which requires a work of high precision, as otherwise the cutting action is poor and the tool faulty. It is for this reason that the cost of such tools is so high. I

Such condition which prevent the manufacture in a large scale at a low cost of the dies more commonly used, are practically eliminated by the improved construction of the present invention. The levelling surface of the cutting edges is held by the bottom surface of a plurality of radial cavities, and by a pressure member so that the radial cavities effected by plain milling and the knives or cutters are accurately made and the manufacture is greatly simplified, to thus make possible the offer to the buyers of an eflicient, safe and durable product, easy and simple to operate and capable of making perfect screw threads.

Finally, the operation of the member pressing the cutting edges is carried out with plain screws, of special shape, which will at the same time act as resting means for the rotation of the member which causes the radial displacement of the cutting edges.

In order that the present invention may be clearly understood and readily carried into efiect, same will hereafter he described with full details with reference to the accompanying illustrative drawings, wherein:

Fig. 1 is a section of a die made according to the invention, the section being effected through the line aa of Figure 2.

Fig. 2 is a front view of the improved die shown in section in Fig. 1.

Fig. 3 is a detail of the mounting of the operative screws, the outer ring and the disc that will cause the radial displacement of the cutting edges.

Fig. 4 shows as seen from its upper face, the annular turnable part that provides for the radial displacement of the cutting edges and which presses them against their seats.

Fig. 5 shows the same turnable annular part of Fig. 4, but seen from its lower face.

Fig. 6 shows a side elevation of a cutting edge of the type used in the device of the present invention.

In all the above figures the same reference numbers designate same or equivalent parts.

With reference to the drawings, the device of the present invention in its application to the making of a die comprises a body 1, of suitable shape, which is longitudinally traversed by the opening 2 which, at one of its ends, is capable of carrying mounted thereon, in some removable manner, the cylindrical guiding member 3 intended to act as'a guide for the part to be worked with the tool of the present invention. The other end of the body is formed with a plurality of segments or sections which, in the example shown, are four and are designated as 4, 5, 6, 7 (but that may be more or less as found convenient) the segments being alternately spaced with free zones 8, 9, 10, 11, and in which segments there has been milled the radial slots 12, 13, 14, 15 intended to receive and at the same time to act as a guide for the cutter 16, the cutter 16 being formed with a projection on its upper surface.

The segments of body 1 are of the height "h and present a turned portion 18 embracing a thickness corresponding to the height hz, so that in the turned zone reduces relative of the segments down to bottom 19 of slot hl, to thus shape a shoulder.

Resting over the turned portion 18 of the segments, there is mounted, turnable, the annular body 20 which, at its lower face is provided with spiral slots 21, as many in number as there are cutters or knives, the said slots tightly lodging projections 17 of the knives. The annular body 20 presents at its upper face, the peripheral turned recess 22 extended over a height indicated in the drawing in Fig. 1 with H. The construction described makes possible the arrangement through suitable means (for example screws not shown) of a retaining ring 23 that is secured on the upper edge of the segments, where the height H1 is larger than the height hz before mentioned.

The cutting edges will be numbered in sequence, and by the given relation existing between the projections 17 thereof and the spiral slots of the annular body 20, the radial direction of the cutting edges will take place when the annular body is angularly displaced.

For the purposes of providing such turning action or to provide for the securing of the cutting edges, the device comprises two or-more recesses 24 provided in the annular body 20, such recesses being of semi-circular shape to make possible within the space comprised between the spirals, threaded holes 25. Within these threaded holes will be lodged screws 26 which are provided with the annular projection 27, and which may be introduced by making notches flush with the recess 28 of the inner edge of retaining ring 23.-

The device operates in the following manner: when the screws are driven downwards, i. e. in the direction of body 1, the annular projection 27 thereof remains far from the reduced edge 28 of the retaining ring 23, and therefore, the annular member 20 may be angularly turned in either direction using for the purpose the screws 7 as handles. The turning of said annular member makes the cutting edges related with the said member through its projections 17, to move radially in either direction according to the movement that has been given to the annularmember. Once the position required of the cutting edges has been obtained, screws 26 are rotated in a reverse direction, that is,.in the direction of the retaining ring, thus making the annular projection of said screws press against the reduced edge 28' of the retaining ring 23, and there will take place the displacement of the annular member 20 downwards, its turning being thereby prevented. The height of the cutter 16 from the lower edge 29 up to the upper edge 30, designated as ha, should be a fraction of a mm. larger than the height h. Thus the annular member 20 will press the cutter against the bottom of the slots which lodge them, thereby securing them in the working position required.

It is to be understood that the present invention is in no way limited tothe example shown and described, but that the same may have various modifications and structural changes without departing in any way from the spirit of the present invention. i

was;

'1: A' threading die' comprising, 'in'combinatiomsupport die members; 'an abutment ring surrounding said cam support means, said abutment ring having an abutting face facing the otherof said facesof said cam disc means discrneansand fixedly connected,tos'aid end'portionof I said -support 1means, 'said abutment ring having an abuttingface facing the "other of said faces of said disc means and being spaced therefrom; and a pair'oflocking means screwed --into "said cam 'disc means, said "locking means located'respectively'on oppositesidesofsaid axis,

each o'fsaid locking means having a locking-face facing said abutting face and located between said other face of said cam disc means and said abuttingface of said'abut- "ment'ring, said locking faces beingmovableffrom a first position where said locking faces are =spacedfrom said abutting face to a second position where "said locking faces are clamped against said abutting face, whereby when said lockingfaces are in said first'position-said cam disc-means isfreely turnable'to adjustsaid die members and when-said locking faces are in said'second position said cam disc'means ispressedagainst said die members so that-saidcam disc'means is prevented fromturning and saiddie members are locked in theirpositions.

' 2. A-threading diecomprising, in-combinatiomsupport means having an axis andan end portion; at'least one pair of diernembers slidably. mounted opposite each other in saidendportion on opposite sides of said-'axis-an'd ad- 'justable'thereto; cam disc means mounted turnably about saidaxis and 'operatively'connectedto said die-members to adjust their position "relative to said axis during-turning movement of saidcam disc means, said cam disc means having a pairof parallel faces substantially normal to said axis and one of said faces bein'gin contactwith said die members; an abutment ring surrounding said cam disc means and'fixedlyconnec'ted to said endportionof said support means, said abutment ring having an abutting fac'e facing the other of said 'faces of said cam disc means "and being spacedtherefrom;; and a'pair of-loc'king means screwed into said cam-disc'mean s, said'locking'means located respectively on opposite sidesof "saidaxisjeach of saidiockingmeans having a locking-face facing said "abutting face andlocatedbetween said other face of "said camdis'c means and said abutting face-of'said abutment Ting, said locking faces being-movable by partly unscrewing said locking means from said cams discmea'ns from a first position where-said locking faces "are *spaced from" said abutting face to a secondiposition where-said locking faces are clamped against "said abutting face, whereby when said locking faces are in saidfirst' position saidcain disc means is freely turnable 'toadjust said die members and when "said locking faces are in'saidj second position said cam disc means is'p'ressed againstisaiddie members so that said cam disc means isiprevented from turning and said die members are loc-ked in their positions.

3. Athreading die comprising, in combinatiom-supp'ort means having an axis and an end portion; atleast onepair of die members slidably mounted opposite each other in said end portion on'opposi'tesides ofsaid'axisand-adjustablethereto; cam disc means mounted turnably about said axis and operativ'ely connectedto said Vdie'members to adjustth'eirposition.relativeitosaid axisduringturning movement of said cam disc means; said camfdiscimeans "having iapair of parallel faces substantially normal to sa'idaxisemd one sofsaid -face'sd'aeirigincontactwith said diem'embers; an'abutment' ring surrounding-said camfdisc means and fixedly' connected :to said end portipnof said and being spaced therefrom; and a pair of locking screws screwed into said cam disc means, said locking screws located respectively on opposite sides of said axis and parallel thereto, each of said locking screws having a flange portion located between said other face of said cam disc means and saidrabutting face of said abutment ring, and each-of said flange portions having a :locking face facing said abutting face, said locking faces being movable by partly unscrewing said locking screws from said cam disc means from a first positiomwhere said locking faces arespaced from said abutting face to asecond position where said locking faces are clamped against said abutting face, whereby when said locking faces are 7 in said first position said cam disc means is freely turnable to adjust said die members and when said locking faces are in said second position said cam disc means is pressed aganst said die members so that said cam disc means is prevented from turning and saiddie members are locked in their positions.

-4. A threadingdie comprising, in combination, support means having an axisand an end portion; atleast one pair of die members slidably mounted opposite eachother in said end portion on opposite -sides-of said axis'and adjustable thereto; cam disc means =mounted turnabl y about said axis and operatively connected to said die members to adjust their position relative -to said axisduring turning movement ofsaid cam disc means,-said cam discmeans -'ha'ving'a pair 'of "parallel faces substantially normal tosaid axis and one ofsaidfaees beingein contact with said die members; an abutment ring-surrounding said cam discmeans and fixedly connected to saidend portion of-said support means, said abutment'ring having an abutting facefac'ing the other of said faces of "said'cam disc meansandbeing spaced therefrom; and a a pair *of locking screws screwed into said cam disc means-and-located respective'ly on -opposite sides of said axis and'lparallel thereto,eac'h of'said locking screwshavinga head portion protruding "beyond saidabutment ring and a flange portion locatedbetween" said other faceof said cam disc means and said abutting face of said abutment-ring, eachof said flangeportions'having a-locking face facing-said-abuttin'g face of said abutment ring, said locking "faces being 'movable by partlyunscrewing said locking screws from said cam disc means from afirst position where said "locking faces are spaced from said abutting face "to "a second position where said lock-ing faces are clamped against said abutting face, whereby when said locking "faces are insaid first position said carn disc means is freely turnable to adjustsaid die members and-when said locking faces are-in said "second position said cam disc means is pressed against said diemembers so-that said cam "disc means is-prevented from turning'and said die members are locked in their positions.

5. A threading die comprising, in combination,a tubular casing having an-axis' andanend -porti0n,-said-end portion having an end face and being formed with at leastapair'of slots extending {in radial direction and respectively on opposite sides of said axis through said tubular casing; a die n iemberslida'blyinounted in each "turnably aboutsaidaxis and operativelyjconnected toeach of said die members to adjust theposition ofsaid'workingface'relative to said'axis duringthe turning movement I of said cam "disc means, said cam "discv'means 'having a "pair of parallel faces -substantially normal to said axis and one of said faces being in'contact'with said end faces of said die members; abutmentj'ring surrounding-said cam discmeans and fixedly connected tosaid en'dportion of said tubular casing, said abutment ring having a :rim

'extendingtransversely to said abutment ring --tozy-npss ward said axis, said rim portion having an abutting face facing the other of said faces of said cam disc means and being spaced therefrom; and a pair of locking screws screwed into said cam disc means, said locking screws located respectively on opposite sides of said axis and parallel thereto, each of said locking screws having a head portion protruding beyond said abutment ring and a flange portion located between said other face of said cam disc means and said abutting face of said rim portion of said abutment ring, each of said flange portions having a locking face facing said abutting face of said n'm portion, said locking faces being movable by partly unscrewing said locking screws from said cam disc means from a first position where said locking faces are spaced from said abutting face to a second position Where said locking 15 faces are clamped against said abutting face, whereby when said locking faces are in said first position said cam disc means is freely turnable to adjust said die members and when said locking faces are in said second position said cam disc means is pressed against said die members so that said cam disc means is prevented from turning and said die members are locked in their positions.

References Cited in the file of this patent UNITED STATES PATENTS 819,868 Downs May 8, 1806 866,300 Platt Sept. 17, 1907 1,342,535 Eden June 8, 1920 

